A long version of OMFG. This longer version is usually used to express an "over the topness" about things. Used in one of two ways. Either sarcastic in nature, or absolutely shocked and amazed. Sometimes this is used when someone says something which - in their mind - is awesome or shocking, but to the respondant, is quite the opposite. On the flip side, sometimes this is just "HOLY SHIT!!!!" type levels of shock and amazement. Either works.